Multiple pass electric heater for fluids



April 24, 1962 G. L. KOESTER, JR 3,031,563

MULTIPLE PAss ELECTRIC HEATER FOR FLUIDE Filed May 25, 1959 2 sheets-sheet I 21 25a-"FHL /z 16 om 2 f6 3a, INVENToR. 7

GEORGE L. KOESTEENE :L .'E. BY T j MKILw/*vmb HTTOENE Ys April 24, 1962 G. L. KOESTER, JR 3,031,563

MULTIPLE PASS ELECTRIC HEATER FOR FLUIDS Filed May 25, 1959 2 Sheets-Sheet 2 "R23 24 (e3 284 za@ 25 e@ HWI N 'llllllllllllllllllrll111111111111111-YIllliiillill'lllllllllv I ||l IIHII I Il 1 I QIIII'M @am W INVENTOR. Geo @Beye L.. KOESTEQJR.

United States Patent 3,031,563 MULTIPLE PASS ELECTRIC HEATER FOR FLUIDS George L. Koester, Jr., Woodclitf Lake, NJ., assignor to Turbine Equipment Company, Westfield, NJ., a corporation of New Jersey Filed May 25, 1959, Ser. No. 815,474 Claims. (Cl. 219-38) This invention relates to electric heaters for fluids and has particular reference to an improved heater of the type in which the fluid is heated electrically as it flows in a tortuous path through the heater.

In heaters of this type as made heretofore, the ilow path for the fluid to be heated is generally defined by a series of baffles arranged in the heater housing and which, in some instances, may contain the electric heating elements. Such prior heaters are relatively costly to manufacture, and their assem-bly and disassembly, as for cleaning or repair, involve operations which are by no means as simple as desired.

The principal object of the present invention is to provide a heater of the type-described which, as compared to prior heaters of this type, can be made at lower cost and is easier to maintain.

The new heater comprises a plurality of heat-conducting panels mounted for sliding movement through one end of the housing and each containing a tortuous channel for passage of the fluid to be heated. These panels extend generally parallel to each other in spaced relation, and in the space between each pair of adjacent panels are means mounting an electric heating assembly forpsliding movement into and out of the housing through one end thereof. Fluid inlet and outlet pipes are interconnected through the channels in the panels, preferably by piping located at an open end portion of the housing where the ends of the tortuous channels in the panels are located. End closure means are releasably secured to the housing and are movable to permit sliding movements of the panels and the heating assemblies through one or both ends of the housing.

With this construction, the passages for the iiuid being heated are completely contained in the panels and the piping by which the panel channels are connected to the heater inlet and outlet. The panels may be disposed in the housing in a drawer-like arrangement, alternating with the electric heating assemblies, and the latter may be slidable through one end of the housing while the panels lare slidable through the opposite end. When the panels have been slid into position in the housing and connected to the piping, the piping serves to hold the panels in position, and by making the piping releasable, the panels may be readily removed individually from the housing.

According to another feature of the invention, the mounting means for each electric heating assembly includes a plate slidably mounted in the space between a pair of adjacent panels and extending substantially parallel to the panels, each plate being slidable into and out of the housing through one end thereof. On each plate, preferably on the opposite faces thereof, are tracks each holding a series of insulators slidable along the track lengthwise thereof and which may be removed from one end of the track. Each track may comprise a pair of opposed strips between which the insulators fit and which are engageable in recesses in the insulators, and the tracks preferably extend lengthwise of the housing. 'Ihe insulators serve to support electric heating elements, such as coils, which may be electrically connected through an end closure of the housing to terminals in a junction box.

For a better understanding of the invention, reference may be had to the accompanying drawings, in which FIG. 1 is a cross-section view of a preferred form of 2 the new electric heater, the section being taken on the line 1-1 in FIG. 2;

FIG. 2 is a sectional view on the line 2 2 in FIG. l;

FIG. 3 is a schematic View of one of the heat-conducting panels illustrated in FIGS. l and 2, showing the tortuous flow path provided by the channel in the panel;

FIG. 4 is an enlarged detail view of part of the heater illustrated in FIGS. 1 and 2, showing the tracks for supporting the electric heating assemblies, and

FIG. 5 is a detailed View of one of the insulators shown in FIGS. l, 2 and 4.

Referring to the drawings, the reference numeral 10 designates a housing which is open at its opposite ends, the housing being provided with top, bottom and opposite side walls. These walls of the housing 10 include suitable insulation material 11 confined between inner and outer plates 12 and 13, respectively. It will be understood that the housing 10 may be fabricated in any suitable manner to provide an enclosure for the electric heating means and the panels through which the fluid flows as it is being heated, and to prevent undue loss of heat from the housing.

Within the housing 10 are channel members 14 extending lengthwise of the housing and secured to the opposite side walls thereof. These channel members are Welded or -otherwise secured to the inner plates `12 of the opposite side walls, the channels on each wall being spaced from each other and being directly opposite the corresponding channels 14 on the opposite side wall. Thus, the adjacent legs of each pair of adjacent channels define a slot or recess extending lengthwise of the housing and form a longitudinal guide 15 which is directly opposed to similar guide on the opposite side wall of the housing 10.

A plurality of heat-conducting panels 16 are slidably mounted in the housing in substantially parallel spaced relation to each other. As shown, each panel 16 has opposite lateral edge portions supported on a pair of opposed gudes 15, these edge portions lbeing received in the longitudinal slots formed by the corresponding guides 15. Accordingly, the panels 16 are slidable on their corresponding guides d5 through one end of the housing 10, so that the panels may be readily slid into position in the housing or removed from the housing. Each panel 16 comprises two sheets of metal embossed at 16a to form a tortuous channel, as indicated at 16b in FIG. 3, the two sheets of each panel being welded or otherwise secured together in face-to-face relation. Panels of this type are well known yand are sold, for example, by Dean Thermo-Panel Coil Division of Dean Products, Inc., Brooklyn, New York, under the name Dean Thermo- Panel Coil. As shown, the ends of the channel in each panel 16 terminate in nipples 16c located at one end of the panel, such a panel being the Type ES Standard Dean Thermo-Panel Coil .sold by said Dean Products, Inc.

A uid inlet pipe 17 extends into one end portion of the housing through one of its side walls. This inlet pipe 17 is connected to one of the nipples 16e of the lowermost panel 16 through a releasable fluid-tight connection 18 of any conventional kind. The other nipple 16C of this panel is connected through a pipe 19 to the overlying nipple of the panel 16 next above, and the other nipple 16C of the latter panel is connected through a pipe 20 to the nipple 16a` of the uppermost panel 16. The other nipple 16e of this top panel is connected to a fluid outlet pipe 21 leading from the housing through its top wall. Thus, the fluid entering the inlet pipe 17 will first flow through the tortuous channel of the bottom panel 16, then through the tortuous channel in the next upper panel 16 and the top panel 16, in that order, and nally discharge from the housing through the outlet pipe.21.

It will be understood that the inlet and outlet nipples 16C of the panels 16- are connected to the pipes 19 and 20 and to the inlet and outlet pipes 17 and 21 through releasable fluid-tight connections 18, so that the panels can be readily disconnected from these pipes to permit sliding of the panels from the housing interior through one end thereof. The inlet and outlet pipes 17 and 21, after being disconnected from the bottom and top panels, may be removed from the housing openings through which they extend, so as to allow removal of these panels from the housing.

It will also be understood that while I have shown the piping arranged for series llow through the panels, the piping may be arranged for parallel flow or parallel-series ilow through the panels from the inlet pipe 17 to the outlet pipe 21. Such parallel ilow may be obtained, for example, by providing a manifold pipe (not shown) connecting the panel nipples 16C at one side of the housing to the inlet pipe 17, and a similar manifold pipe (not shown) connecting the panel nipples 16e at the opposite side of the housing to the outlet pipe 21.

In the space between each adjacent pair of panels 16 is a plate 23 having its opposite lateral edge portions received in the longitudinal slots formed by corresponding opposed guides 15. Thus, the plates 23 are slidable into and out of the. housing through one end thereof in the same manner as the panels 16. The legs or anges 24 of the channel members 14 adjacent the top and bottom of the housing are spaced therefrom to form longitudinal slots for receiving the opposite lateral edge portions of similar plates 23a. On each face of the plates Z3, and on the inner face of each plate 23a, are channel members 25 extending lengthwise of the housing, the bases of members 25 being Welded or otherwisesecured to the plates. Each channel member 25 has opposed legs 26 projecting from the plate and turned inwardly toward each other at their free ends to form hooks 26a. The legs 2.6 of each channel member are, in effect, exible longitudinal strips forming a track for retaining a series of insulators 28.

Each insulator 28, as shown more particularly in FIG. 5, has recesses or grooves 28a at each end portion, these grooves extending along the upper and lower surfaces of the insulator lengthwise. of the tracks 26. The opposite ends of each insulator are provided with spacer ilanges 28h, so that the insulator in plan View is generally H-shaped, as shown in FIG. 5. Holes 28C extend through the insulator from front to rear and are spaced apart transversely of the tracks 26.

The insulators in each channel member 25 are held on the corresponding plate 23 or 23a by the opposed strips forming the track 26. As shown particularly in FIG. 4, the hooks 26a at the free edges of the strips 26 engage in the adjacent recesses 26a of each insulator in the track. Thus, each track 26 holds a series of insulators 28 on the corresponding plate 23, with the holes 28e of the insulators in alignment lengthwise of the housing, and with the main bodies of the insulators spaced from each other by the flanges 28b.

With this arrangement, each of the plates 23`and 23a, with their assembled rows of insulators 28, may be slid into or out of the housing 10l through one end thereof on the respective opposed guides and 24. Also, the

insulators 2S in each row may be slid lengthwise of the corresponding track 26 to remove the insulators from the plate 23 ork 23a on which they are mounted, thereby permitting easy replacement of an insulator and facili- Y tating assembly of the insulators. It willalso be apparent that each panel 16 islocated between rows of insulators 28 extending both above and below the panel.

The insulators 28 opposite each face of each panel 16 form part of an electric heating assembly which also comprises an electric heating element supported by the insulators. As illustrated, this heating element is in the form of a wire coil 29 extending Vthrough theholes 28C to form a suitable winding. It will be understoodV that the heating coil 29l opposite each face of each panel 16 may be wound in any suitable manner on the corresponding rows of insulators 28.

The front end of housing lil is closed by a removable closure member 30 provided with suitable insulation. At its rear end, the housing 10 is closed by another removable closure member 31 which is likewise insulated. The members 30 and 31 are releasably secured in their closing position in any suitable manner. Thus, these members form releasable end closure means which are movable to permit sliding the panels 16 and plates 23-23a into or out of the housing 10. When the heater is assembled, such sliding of these parts is prevented by the piping 17, 19', 20 and 21 and the rear closure member 31 which abuts against the rear ends of the panels 16 and the plates 23-23a. If desired, supplemental means such as releasable stops (not shown) may be provided in the front end portion of the housing to hold the plates 23-23a against the rear closure member 31.

The rear closure member 31 has holes 32 for passage of the electrical connections (not shown) to the heating elements 29 from a junction box or terminal box 33 secured to the corresponding end of the housing. Through a tting 34, a cable (not shown) may be led into the junction `box 33 to supply the electric current for energizing the heating elements 29. The box 33 may be releasably secured to the housing 10 so that when it is removed with closure member 31, the plates 23a-23a and panels 16 may be slid from thel housing through the back thereof.

It will be apparent that the new heater, as illustrated, is of simple construction `and can be readily assembled or disassembled, by reason of the drawer-like arrangement of the panels 16 and the plates 23-23a. Also, the new heater may be readily adapted for series ilow, parallel flow, or series-parallel flow of the -uid to be heated, by proper arrangement of the piping by which the fluid inlet and outlet are interconnected through the channels in panels 16, this piping being easily accessible lfrom the front of the housing by removing the closure member 30.

'It will be understood that the illustrated lforrn of the new heater may be modified in various respects to suit the requirements of a particular installation. For example, instead of providing releasable pipe connections extending to and Ibetween the heat-conducting panels 16, the latter may be connected by welded piping, which can be removed by a simple cut and then re-welded.

I claim:

1. An electric heater comprising a housing having at least one open end, a plurality of pairs of opposed panel guides in the housing extending lengthwise thereof, a plurality of heat-conducting panels in the housing extending generally parallel to each other in spaced relation and each having opposite lateral edge portions slidably supported on a corresponding pair of opposed panel guides, each panel containing a tortuous throughoyv channel and being slidable endwise on its guides into and out of the housing through one end thereof, each panel also having an inlet to its channel and lan outlet from its` channel, each inlet and outlet being located at said open end of the housing, an electric heating assembly located in the space between each pair of adjacent panels, each heating assembly including a plate, a plurality of strips secured to the plate, insulators slidably secured to the plate by the strips and arranged in generally parallel rows each of which is slidable along a corresponding strip to remove the row from the plate, and a plurality of electric heating elements extending generally parallel to said rows and each releasably supported by the insulators in one of said rows, means mounting each heating assembly plate independently of the panels and each other plate for sliding movement endwiseinto and out of the housing through open end thereof, fluid inlet and outlet pipes, and piping communicating with the inlets and outlets of the panels and located opposite corresponding endportions of the panels, said piping being disposed at least partly in said open end of the housing and interconnecting the inlet and outlet pipes through the channels in said panels.

2. An electric heater according to claim 1, in which the housing is open at both ends and comprising also end closure means releasably secured to the housing and movable to permit said sliding movements of the panels and heating assemblies.

3. An electric heater according to claim 1, in which the housing is open at both ends and comprising also end closure means releasably secured to the housing and movable to permit said sliding movements of the panels and heating assemblies, said end closure means including a movable member closing each end of the housing, one of the closure members having electrical conductor passages leading to the electric heating assemblies.

4. An electric heater according to claim 1, in which the housing is open at both ends and comprising also end closure means releasably secured to the housing and movable to permit said sliding movements of the panels and heating assemblies, said end closure means including a movable member closing each end of the housing, one of the closure members having electrical conductor passages leading to the electric heating assemblies, the heater comprising also means forming with said one closure member a terminal box.

5. An electric heater according to claim 1, in which the housing is open at both ends comprising also a movable closure member closing each end of the housing, one of the closure members having electrical conductor pas.- sages leading to the electric heating assemblies, said pipin-g being located between the other closure member and adjacent ends of the panels and heating assemblies.

6. An electric heater according to claim 1, in which Said mounting means include a pair of opposed plate guides in the space -between each part of adjacent panels.

7. An electric heater according to claim 1, in which said rows of insulators extend lengthwise of the housing, whereby the insulators can be slid relative to the plates through said open end of the housing.

8. An electric heater according to claim 1, in which said strips are disposed in pairs, one pair for each row of insulators, each insulator having recesses in which the strips of a corresponding pair are engaged and being slidable between the strips of said pair.

9. An electric heater according to claim 1, in which each plate is provided on both sides thereof with said strips, insulators and electric heating elements.

10. An electric heater according to claim 1, in which each insulator has a flange adjacent the corresponding strip land servin-g as a spacer for the main body of the insulator in the corresponding row.

References Cited in the le of this patent UNITED STATES PATENTS 631,838 Witherspoon Aug. 29, 1899 1,036,990 Foster Aug. 27, 1912 1,188,972 Moiat n- June 27, 1916 1,226,849 Bookman May 22, 1917 1,574,053 Nesmith Feb. 23, 1926 1,626,656 Woodson May 3, 1927 1,820,458 Jenkins Aug. 25, 1931 2,729,433 Berg Jan. 3, 1956 

